OpenSSL support

This was a card but now it's an issue too. ;)

We need OpenSSL integration for the native image target. Here are the requirements:

• Replace any/all usages of the JCA with libssl and/or libcrypto direct C calls
  • This should be done by implementing each crypto primitive with an implementation class; then we should swap out calls to e.g. MessageDigest.getInstance("SHA-256") with our own e.g. new OpenSslSHA256MessageDigest(); this is probably best accomplished using a Feature with a node plugin that swaps the invocation sites
  • Unknown algorithms should be translated to throw new NoSuchAlgorithmException()
• Support dynamic run-time linking of OpenSSL implementation
  • This is done via dlsym and CFunctionPointer objects

Acceptance criteria:

• JSSE/JCA functions correctly :)
• Run time image size is not significantly increased